We can only imagine what it would have been like to live at the time of the Prophet (PBUH) and to be alive in his lifetime with the Sahaba. Can you imagine sitting round listening to the teaching of our Prophet (PBUH)!!!
The prophet wore a silver ring on his pinky finger to seal letters that he sent to rulers around the world. This was the only way they would read the letters. It showed that the letters were genuinely sent from the Prophet (PBUH) himself.
Narrated Anas bin Malik:
Once the Prophet (ﷺ) wrote a letter or had an idea of writing a letter. The Prophet (ﷺ) was told that they (rulers) would not read letters unless they were sealed. So the Prophet (ﷺ) got a silver ring made with “Muhammad Allah’s Messenger (ﷺ)” engraved on it. As if I were just observing its white glitter in the hand of the Prophet.
حَدَّثَنَا مُحَمَّدُ بْنُ مُقَاتِلٍ أَبُو الْحَسَنِ، أَخْبَرَنَا عَبْدُ اللَّهِ، قَالَ أَخْبَرَنَا شُعْبَةُ، عَنْ قَتَادَةَ، عَنْ أَنَسِ بْنِ مَالِكٍ، قَالَ كَتَبَ النَّبِيُّ صلى الله عليه وسلم كِتَابًا ـ أَوْ أَرَادَ أَنْ يَكْتُبَ ـ فَقِيلَ لَهُ إِنَّهُمْ لاَ يَقْرَءُونَ كِتَابًا إِلاَّ مَخْتُومًا. فَاتَّخَذَ خَاتَمًا مِنْ فِضَّةٍ نَقْشُهُ مُحَمَّدٌ رَسُولُ اللَّهِ. كَأَنِّي أَنْظُرُ إِلَى بَيَاضِهِ فِي يَدِهِ. فَقُلْتُ لِقَتَادَةَ مَنْ قَالَ نَقْشُهُ مُحَمَّدٌ رَسُولُ اللَّهِ قَالَ أَنَسٌ.
Reference : Sahih al-Bukhari 65
In-book reference : Book 3, Hadith 7
USC-MSA web (English) reference : Vol. 1, Book 3, Hadith 65
(deprecated numbering scheme)